The weather forecast for San Fernando this Monday, September 21, indicates that the maximum temperature will be 17°C and the minimum 10°C.

Additionally, according to the National Meteorological Service (SMN), winds of 23 km/h are expected, and average humidity will be 77%.

Weather forecast for San Fernando for the morning of September 21, 2026

The SMN report states that during the early hours of this Monday, September 21, conditions will remain dry, humidity will be 77%, and moderate westerly winds of 23 km/h are expected.

Meanwhile, by mid-morning, conditions will remain dry, humidity will be 45%, and there will be moderate southwesterly winds of 31 km/h.

Weather forecast for the afternoon/evening of September 21, 2026

According to the agency's forecast for San Fernando, this afternoon conditions will remain dry, with moderate southwesterly winds of 35 km/h expected.

Meanwhile, tonight, conditions will remain dry, with moderate southwesterly winds of 26 km/h.

What is the National Meteorological Service and how does it work

The National Meteorological Service (SMN) is the official agency responsible for collecting, analyzing, and disseminating meteorological information across the country. Its main function is to predict climate and weather conditions, issue early warnings about dangerous meteorological phenomena, and provide climate information for various activities, such as aviation, agriculture, and navigation.

The SMN operates through a network of weather stations distributed throughout the country, in addition to using satellite imagery and numerical prediction models.

What is a weather alert in San Fernando

The agency itself refers to an alert as "the possible occurrence of a meteorological threat," which it issues with the aim of supporting decision-making across all sectors of the population. These are generally issued 24, 48, or 72 hours before the event. On the other hand, very short-term advisories (ACP) urge the population to take action quickly, as the phenomenon may occur just minutes after its issuance.

An alert can be issued in situations involving rain or storms, or in the face of extreme temperatures or phenomena that deviate from usual conditions.

What is a yellow alert

These involve possible meteorological phenomena with the potential for damage and risk of momentary disruption to daily activities, according to the SMN.

In the case of high temperatures, the yellow level indicates that they may be dangerous, especially for at-risk groups, such as children, people over 65, and those with chronic illnesses.

What is an orange alert

This warning indicates that meteorological phenomena dangerous to society, life, property, and the environment are expected. In this case, temperatures may be very dangerous, especially for at-risk groups.

What is a red alert

The agency's website warns of "exceptional meteorological phenomena with the potential to cause emergencies or disasters."

In this type of alert, temperatures are "very dangerous and can affect all people, even those who are healthy."

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